This invention relates to the field of dental prosthetic implants. More particularly, this invention is directed to an improved dental prosthetic implant with enhanced angular rotation and locking capabilities once the abutment has been positioned in a preferred position relative to the implant fixture.
The field of dental prosthetic devices is a rapidly growing industry with dental implants beginning to garner an increased market share as opposed to the old-fashioned removable dentures, partial dentures or conventional bridges. A large number of implant systems have been developed by individuals wanting to sink their teeth into this expanding piece of pie.
These systems are typically comprised of two principal components: an implant fixture that is imbedded into the jaw bone (maxilla or mandible) of the patient, and an abutment which typically forms a support for the prosthesis, i.e., a crown, a denture, partial or bridge abutment. The implant fixture will be surgically implanted at an angle that will vary based on a plurality of factors: the number of implants being placed into the corresponding section of bone that is edentulous, that portion of the edentulous area that has the most bone support to place the implant with the greatest success, and the angle chosen by the professional that is placing the implant. The abutment, on the otherhand, needs to be positioned relative to its opposing tooth so that proper occlusion may result for good function.
In some systems, a myriad of shims of varying angularity are used between the implant fixture and the abutment to provide the desired relative positioning for these two elements to ensure proper occlusion. Such an implant system is complicated by literally hundreds of different pieces which must be properly selected and assembled. There are other systems that use pre-fabricated angled abutments, but these systems have problems relative to their rotational locations.
More recently, the abutment has been attached to the implant fixture by a ball-and-socket joint and a set screw has been used to lock the two elements into the desired angular and rotational position. The problem with these systems is that the force exerted by the muscles of mastication can exceed 250 lbs/sq.in. which, when applied near the edge of a biting or chewing surface, can produce torsional forces capable of overpowering the retention force created by the relatively small frictional surface area of the set screw, thereby displacing the prosthetic tooth.
Therefore, the present invention provides a dental prosthetic implant with an enhanced rotational and locking capability. It further provides an implant that is designed for proper hygene significantly reducing the potential for micro-leakage. Lastly, the implant of this invention provides a system which has been designed to use significantly fewer pieces than prominent previous systems.
These features are provided by a dental implant fixture and positionable abutment. The abutment has a plurality of flexible fingers which can be expanded by virtue of a locking screw into engagement with a portion of the implant fixture to secure the abutment in a particular rotational and/or pivotal position. The portion of the abutment containing the flexible fingers may be formed integrally on a separate element which is secured to the main body by virtue of a retaining protrusion on the locking screw or formed integrally with the main body of the abutment.
In one embodiment, a retaining ring is formed on the locking screw to secure it to a separable ball element of the abutment. The actuating portion of the flexible fingers and associated portion of the locking screw may be tapered outwardly so the locking screw acts in tension and provides an upwardly and outwardly directed force or, alternatively, these portions may be tapered inwardly so that the locking screw acts in compression so the locking screw provides a downwardly and outwardly directed force. In either case, the flexible fingers interact with a complementary surface on the implant fixture to secure the abutment against undesired rotational and/or pivotal movement.
Various other features advantages and characteristics of the present invention will become apparent after a reading of the following detailed description of the preferred embodiments.